A technique called CCN (content centric network), which is disclosed in Non-Patent Literature (hereinafter, referred to as “NPL”) 1, has attracted attention in recent years. CCN is a content distribution platform to manage a content based on the name of the content.
In CCN, the contents to be distributed, or data pieces obtained by splitting a content are named in advance. A terminal that acquires a content issues a packet called “interest packet” to request transmission of a content by specifying the name of the content (hereinafter, referred to as “content name”).
Upon reception of an interest packet, a terminal that has published a content transmits a content corresponding to the content name specified by the interest packet to the terminal which is the transmitter of the interest packet. In this way, each terminal can acquire the content based on the content name without knowing where the content is. Hereinafter, the terminal that has published the content will be referred to as “transmission terminal” and the terminal that transmits an interest packet to attempt to receive content data will be referred to as “reception terminal.”
CCN has an advantage that a content can be acquired from a router that has transferred the content in the past. In CCN, each router caches (temporarily stores) contents to be transferred from a transmission terminal to a reception terminal. If a content specified by a received interest packet is included in the cached contents, the router transmits the content to the reception terminal. In this way, in CCN, contents can be transmitted to the reception terminal without retransmission of the content from the transmission terminal to the router.
CCN capable of efficiently distributing contents is expected to be applied to a public communication network such as the Internet.
However, as represented by the Internet, many public communication networks are best-effort type communication networks. For this reason, with a best-effort type communication network, there may be missing (packet loss) in received data in interest packets or data packets due to congestion in the communication network or data being garbled during transmission or the like.
Thus, PTL 1 discloses retransmission of interest packets. Even when packet loss occurs, retransmission of interest packets allows data to be received later and can improve reliability of data delivery.